Enamel hardener is a relativly new compound, I don't think the the enamels of 40, 50 or 60 years ago used a hardener. They were thined with an enamel reducer and simply cured by oxidation. That was why they forced dried them with heat ovens at the factorys and better paint shops. Generally in the body and paint shops it would take over night (24hrs) for the paint to set up and around a month before you could wax or clean it. Also the older enamels gave you a high gloss and they were not rubbed out like a lacquer job. If you tried rubbing them out with a buffer you killed the gloss.

Rustoleum is enamel keith, not lacquer. And the old paint, factory and repaint holds up just fine gasoline doesn't touch it.
Also the AD trucks were painted with enamel and the cars with lacquer back then.

Denny G

Denny G
Sandwich, IL